Implantation bleeding?

I have been trying to get pregnant since I found out I had pcos in February. My period was late in March because I was taking meds for BV. I started spotting 4/14 then 4/15-4/18 was a normal "period" then 4/19 to today 4/23 I have had off n on pink spotting (one time brown) and today I feel nausea. I have read that working out can cause spotting but I don't spot right after I work out (20-30 mins a day) is this implantation bleeding and if so when should I test?